Driving method for an image pickup apparatus, image pickup apparatus, and image pickup system

Abstract

The present invention provides a driving method for an image pickup apparatus that appropriately performs both readout of a signal of a reference pixel and mixing of mutual signals output by a plurality of effective pixels, and the present invention also provides an image pickup apparatus and an image pickup system.

What is claimed is: 
     
       1. A driving method for an image pickup apparatus that includes a plurality of pixels arranged in rows and columns, and a plurality of signal lines each being arranged corresponding to one of the columns of the plurality of pixels,
 the plurality of pixels including
 a plurality of effective pixels arranged in the rows and the columns, and 
 a plurality of reference pixels arranged in at least one row and the columns corresponding to the columns in which the plurality of effective pixels are arranged and outputting only a signal of a noise level, 
 
 each of the plurality of effective pixels including a photoelectric conversion unit to perform a photoelectric conversion of incident light and an amplification transistor having an input node for inputting charges generated by the photoelectric conversion unit, and 
 each of the plurality of reference pixels including an amplification transistor having an input node, 
 the driving method comprising: 
 a first operation of overlapping periods, without electrically connecting the input node of the amplification transistor in each of a first number of effective pixels among the plurality of effective pixels, to each other, each period being a period during which the amplification transistor in each of the first number of effective pixels outputs a signal to common one of the signal lines, and 
 a second operation of:
 individually outputting the signal of the noise level to the single signal line by the amplification transistor in each of the plurality of reference pixels, or 
 overlapping periods, without electrically connecting the input node of the amplification transistor in each of a second number of reference pixels among the plurality of reference pixels, to each other, each period being a period during which the amplification transistor in each of the second number of reference pixels outputs a signal common one of the signal lines, the second number being fewer than the first number. 
 
 
     
     
       2. The driving method for the image pickup apparatus according to  claim 1 ,
 wherein each of the plurality of reference pixels further includes a floating diffusion unit and a reset transistor that controls ON and OFF of reset of the floating diffusion unit on the basis of a control voltage output to a control node, and the amplification transistor outputs a signal based on a potential at the floating diffusion unit to the signal line, 
 wherein each of the plurality of effective pixels further includes a floating diffusion unit and a reset transistor that controls ON and OFF of reset of the floating diffusion unit on the basis of a control voltage output to a control node, the charges are output from the photoelectric conversion unit to the floating diffusion unit, and the amplification transistor outputs a signal based on a potential at the floating diffusion unit to the signal line, and 
 wherein a voltage difference of the control voltage between ON and OFF of the reset transistor in each of the plurality of reference pixels is set to be smaller than a voltage difference of the control voltage between ON and OFF of the reset transistor in the effective pixel. 
 
     
     
       3. The driving method for the image pickup apparatus according to  claim 1 ,
 wherein each of the plurality of reference pixels further includes a floating diffusion unit and a reset transistor that controls ON and OFF of reset of the floating diffusion unit on the basis of a control voltage output to a control node, and the amplification transistor outputs a signal based on a potential at the floating diffusion unit to the signal line, 
 wherein each of the plurality of effective pixels further includes a floating diffusion unit and a reset transistor that controls ON and OFF of reset of the floating diffusion unit on the basis of a control voltage output to a control node, the charges are output from the photoelectric conversion unit to the floating diffusion unit, and the amplification transistor outputs a signal based on a potential at the floating diffusion unit to the signal line, and 
 wherein, in a first frame period during which the first operation is performed and a second frame period during which signals are read out from the plurality of effective pixels without performing the first operation, 
 a voltage difference of the control voltage between ON and OFF of the reset transistor in the plurality of reference pixels and the plurality of effective pixels in the first frame period is set to be smaller than a voltage difference of the control voltage between ON and OFF of the reset transistor in the plurality of reference pixels and the plurality of effective pixels in the second frame period. 
 
     
     
       4. The driving method for the image pickup apparatus according to  claim 1 ,
 wherein each of the plurality of reference pixels and the amplification transistor provided in each of the plurality of pixels perform a source follower operation by using a current supplied to the signal line and a voltage supplied to the amplification transistor, and 
 wherein a current value of the current supplied to the signal line in the second operation is set to be higher than a current value of the current supplied to the signal line in the first operation. 
 
     
     
       5. The driving method for the image pickup apparatus according to  claim 1 ,
 wherein each of the plurality of reference pixels and the amplification transistor provided in each of the plurality of pixels perform a source follower operation by using a current supplied to the signal line, and 
 wherein, in a first frame period during which the first operation is performed and a second frame period during which signals are read out from the plurality of effective pixels without performing the first operation, 
 a current value of the current supplied to the signal line in the second frame period is set to be higher than a current value of the current supplied to the signal line in the first frame period. 
 
     
     
       6. The driving method for the image pickup apparatus according to  claim 1 ,
 wherein the plurality of pixels include a focus detection pixel including a photoelectric conversion unit obtained by shielding light in a part of the photoelectric conversion unit, and 
 wherein a signal is read out from the amplification transistor in the focus detection pixel in the second operation. 
 
     
     
       7. The driving method for the image pickup apparatus according to  claim 1 ,
 wherein each of the plurality of reference pixels includes a light-shielded photoelectric conversion unit, and the amplification transistor in each of the plurality of reference pixels outputs a signal based on charges of the light-shielded photoelectric conversion unit. 
 
     
     
       8. The driving method for the image pickup apparatus according to  claim 1 ,
 wherein each of the plurality of reference pixels includes a floating diffusion unit, a light-shielded photoelectric conversion unit, and a transfer transistor that controls ON and OFF of transfer of charges from the light-shielded photoelectric conversion unit to the floating diffusion unit on the basis of a control voltage output to a control node, and the amplification transistor outputs a signal based on a potential at the floating diffusion unit to the signal line, 
 wherein each of the plurality of effective pixels includes a floating diffusion unit and a transfer transistor that controls ON and OFF of transfer of charges from the light-shielded photoelectric conversion unit to the floating diffusion unit on the basis of a control voltage output to a control node, and the amplification transistor outputs a signal based on a potential at the floating diffusion unit to the signal line, and 
 wherein a voltage difference of the control voltage between ON and OFF of the transfer transistor in the reference pixel is set to be smaller than a voltage difference of the control voltage between ON and OFF of the transfer transistor in the effective pixel. 
 
     
     
       9. The driving method for the image pickup apparatus according to  claim 1 ,
 wherein each of the plurality of reference pixels includes a floating diffusion unit, a light-shielded photoelectric conversion unit, and a transfer transistor that controls ON and OFF of transfer of charges from the light-shielded photoelectric conversion unit to the floating diffusion unit on the basis of a control voltage output to a control node, and the amplification transistor outputs a signal based on a potential at the floating diffusion unit to the signal line, 
 wherein each of the plurality of effective pixels includes a floating diffusion unit and a transfer transistor that controls ON and OFF of transfer of charges from the light-shielded photoelectric conversion unit to the floating diffusion unit on the basis of a control voltage output to a control node, and the amplification transistor outputs a signal based on a potential at the floating diffusion unit to the signal line, and 
 wherein, in a first frame period during which the first operation is performed and a second frame period during which signals are read out from the plurality of effective pixels without performing the first operation, 
 a voltage difference of the control voltage between ON and OFF of the transfer transistor in each of the plurality of reference pixels and the plurality of effective pixels in the first frame period is set to be smaller than a voltage difference of the control voltage between ON and OFF of the transfer transistor in each of the plurality of reference pixels and the plurality of effective pixels in the second frame period. 
 
     
     
       10. The driving method for the image pickup apparatus according to  claim 1 ,
 wherein each of the plurality of pixels further includes a selection transistor with which an electric path between the amplification transistor and the signal line is put into a conductive state when the selection transistor is set in an ON state, and the electric path is put into a non-conductive state when the selection transistor is set in an OFF state, 
 wherein, the connecting the plurality of amplification transistors in the first number of the plurality of effective pixels in the first operation, is performed by setting in the ON state of a plurality of selection transistors in the first number of the plurality of effective pixels, 
 wherein, the connecting the plurality of amplification transistors in the second number of the plurality of reference pixels in the second operation, is performed by setting in the ON state of a plurality of selection transistors in the second number of the plurality of reference pixels. 
 
     
     
       11. A driving method for an image pickup apparatus that includes a plurality of pixels arranged in rows and columns, and a plurality of signal lines each being arranged correspond to one of the columns of the plurality of pixels,
 the plurality of pixels including a plurality of effective pixels arranged in the rows and the columns, and reference pixels arranged in at least one row and the columns corresponding to the columns in which the plurality of effective pixels are arranged, 
 each of the plurality of effective pixels including a photoelectric conversion unit to perform a photoelectric conversion of incident light and an amplification transistor having an input node for inputting charges generated by the photoelectric conversion unit, and 
 each of the plurality of reference pixels including a light-shielded photoelectric conversion unit and an amplification transistor having an input node, 
 the driving method comprising: 
 a first operation of overlapping periods, without electrically connecting the input node of the amplification transistor in each of a first number of effective pixels among the plurality of effective pixels, to each other, each period being a period during which the amplification transistor in each of the first number of effective pixels outputs a signal to common one of the signal lines, and 
 a second operation of:
 individually outputting the signal of the noise level to the single signal line by the amplification transistor in each of the plurality of reference pixels, or 
 overlapping periods, without electrically connecting the input node of the amplification transistor in each of a second number of reference pixels among the plurality of reference pixels to the other of the plurality of reference pixels, to each other, each period being a period during which the amplification transistor in each of the second number of reference pixels outputs a signal to common one of signal lines, the second number being fewer than the first number. 
 
 
     
     
       12. An image pickup apparatus comprising:
 a plurality of pixels arranged in rows and columns; 
 a plurality of signal lines each being arranged to correspond to one of the columns of the plurality of pixels; and 
 a control unit that causes the plurality of pixels to perform both a first operation and a second operation, 
 the plurality of pixels including a plurality of effective pixels arranged in the rows and the columns, and a plurality of reference pixels that are arranged in at least one row and the columns corresponding to the columns in which the plurality of effective pixels are arranged and output only a signal of a noise level, 
 each of the plurality of effective pixels including a photoelectric conversion unit to perform a photoelectric conversion of incident light and an amplification transistor having an input node to which charges generated by the photoelectric conversion unit are input, and 
 each of the plurality of reference pixels including an amplification transistor having an input node, 
 wherein the first operation is an operation of overlapping periods, without electrically connecting the input node of the amplification transistor in each of a first number of effective pixels among the plurality of effective pixels, to each other, each period being a period during which the amplification transistor in each of the first number of effective pixels outputs a signal to common one of the signal lines, and 
 wherein the second operation is an operation of:
 individually outputting the signal of the noise level to the single signal line by the amplification transistor in each of the plurality of reference pixels, or 
 overlapping periods, without electrically connecting the input node of the amplification transistor in each of the second number of reference pixels among the plurality of reference pixels, to each other, each period is a period during which the amplification transistor in each of the second number of the reference pixels output a signal to common one of the signal lines, the second number being fewer than the first number. 
 
 
     
     
       13. The image pickup apparatus according to  claim 12 ,
 wherein the control unit includes a scanning circuit. 
 
     
     
       14. The image pickup apparatus according to  claim 12 ,
 wherein the plurality of pixels include a focus detection pixel including a photoelectric conversion unit obtained by shielding light in a part of the photoelectric conversion unit, and 
 wherein a signal is read out from the amplification transistor in the focus detection pixel in the second operation. 
 
     
     
       15. The image pickup apparatus according to  claim 12 , wherein each of the plurality of reference pixels includes a light-shielded photoelectric conversion unit, and the amplification transistor in each of the plurality of reference pixels outputs a signal based on charges of the light-shielded photoelectric conversion unit. 
     
     
       16. An image pickup system comprising:
 an image pickup apparatus; and 
 an output signal processing unit that processes a signal output from the image pickup apparatus to generate an image, 
 wherein the image pickup apparatus comprises: 
 a plurality of pixels arranged in rows and columns, 
 a plurality of signal lines each being arranged to correspond to one of the columns of the plurality of pixels, and 
 a control unit that causes the plurality of pixels to perform both a first operation and a second operation, 
 the plurality of pixels including a plurality of effective pixels arranged in the rows and the columns, and a plurality of reference pixels arranged in at least one row and the columns corresponding to the columns in which the plurality of effective pixels are arranged and outputting only a signal of a noise level, 
 each of the plurality of effective pixels including a photoelectric conversion unit to perform a photoelectric conversion of incident light and an amplification transistor having an input node for inputting charges generated by the photoelectric conversion unit are input, and 
 each of the plurality of reference pixels including an amplification transistor having an input node, 
 wherein the first operation is an operation of overlapping periods, without electrically connecting the input node of the amplification transistor in each of a first number of effective pixels among the plurality of effective pixels, to each other, each period being a period during which the amplification transistor in each of the first number of effective pixels outputs a signal to common one of the signal lines, and 
 wherein the second operation is an operation of:
 individually outputting the signal of the noise level to the single signal line by the amplification transistor in each of the plurality of reference pixels, or 
 overlapping periods, without electrically connecting the input node of the amplification transistor in each of a second number of reference pixels among the plurality of reference pixels, to each other, each period being a period during which the amplification transistor in each of the second number of reference pixels outputs a signal common one of the signal lines, the second number being fewer than the first number. 
 
 
     
     
       17. The image pickup system according to  claim 16  comprising:
 an optical system that guides the incident light to the image pickup apparatus, 
 wherein the plurality of pixels includes a focus detection pixel including a photoelectric conversion unit obtained by shielding light in a part of the photoelectric conversion unit, 
 wherein a signal is read out from the amplification transistor in the focus detection pixel in the second operation, 
 wherein the image pickup apparatus outputs a focus detection signal based on a signal output by the focus detection pixel and an image pickup signal based on signals output by the plurality of effective pixels to the output signal processing unit, and 
 wherein the output signal processing unit detects whether or not a focus state is established on the basis of the focus detection signal and also generates the image by using the image pickup signal.